In a case where an alphabetic letter is entered in a general input mode, an alphabetic letter is entered while shifting the input mode to a capital letter input mode or a small letter input mode through an input of a Caps Lock key.
Especially, in a case where a character input as a small letter among alphabetic letters of an already input word is desired to be changed to a capital letter or a character input as a capital letter is desired to be changed to a small letter, it is inconveniently necessary to select and delete a corresponding character, switch the input mode to a capital input mode or a small letter input mode by inputting a Caps Lock key, and then input a letter again.